1084 usable hardness

H

Hesparus

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Oct 31, 2004
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Hi Everyone,

I've got a batch of knives that includes several kitchen knives that I'm just about ready to send to Peter's. Most of the kitchen knives are of the Japanese variety, which tend to have hardnesses in the 61-64 range. My question is how high can 1084 go? I know that the as-quenched hardness can be as high as 65, but how close can you get to that before it gets too brittle to use for a kitchen knife? I've got a gyuto, a kiritsuke, a yanagiba, a sujihiki, and several pettys.
Thanks,
Chris
 
Funny you ask! I was contemplating the exact same question this morning. I will stay tuned for an answer.
 
I made a gyuto from 1084/15N20 damascus and tempered it at 375 which with straight 1084 would give you say 62-63. I do 1084 hunters at 400 whihc give me maybe 61. No problem. I treat it the same way as W2 and expect it to be a point or so softer for the same temper. Go to Cahsenblades.com. Kevin has heat treat info for it.
 
I have several 1084 blades I tempered at 350 that tested at Rc62-63. I have had no chipping or cracking issues.
scott
 
While 1084 will work for those knives, it is not the optimal steel. There is more to matching a steel to a knife use than final hardness. A chart of steel characteristics and comparison is a good tool when deciding. Some steels are very tough, but don't work well hard. Others get very hard, but don't have good edge retention. What is best is a balance of toughness and wear resistance in the optimal hardness range for the chosen knife use.
What makes a good kitchen knife is sacrificing some toughness for more usable hardness.

Japanese style knives take this even farther, as they have very thin edge geometry. This is the realm of the high wear and high hardness stainless steels, and the higher carbon steels. 1095, 52100, W2, are all a better choice than 1084.
For the ultimate steel choice in making Japanese kitchen knives, Hitachi blue or white steel is the steel of choice.

1084 should be used at Rc 58-60 for the best edge balance, but could be pushed to Rc 61, maybe Rc 62, if the knife is used gently. Other steels can be taken to Rc 63-64 and still hold up in use....when used carefully.
 
Thanks for the comments, everyone.
Stacy: I knew there was more to steel than final hardness, and I didn't know what that meant for 1084. Your response is exactly what I was looking for. I've already decided to upgrade to 52100 for my next round of kitchen knives.

- Chris
 
Just wondering about the theory of things, but in theory, couldn't 1084 take a finer edge because it forms very few carbides?
 
The carbides in 1095/W2 are not the same as the big alloy carbides in stainless steel. We are talking about simple iron carbide here. If the steel is normalized starting at a high enough temp, and held long enough for the carbides to go fully into solution, then the grain is reduced with subsequent quenches from lower temps, the harder edge of the higher carbon steel will be a better cutter because it will last longer. The 1084 edge will be about the same fineness of grain, maybe a tad finer, but that will not make any difference in cutting ability. A very thin edge on the 1084 will be gone after only a few cuts. The higher carbon blade will have a harder and tougher edge and thus cut better and longer.
 
When matching steel with intended usage, I tend to separate it by the three steel types. Not always... but it is a decent starting point.

Slicers that require high hardness - Hypereutectoid
General cutters and utility knives - Eutectoid
Choppers and blades that would see impact - Hypoeutectoid
 
At the risk of being difficult, (not intended) this is exactly what I was referring to when discussing visual learning strategies. Rick organized the information into a general framework that helps organize the information. Greatly appreciated. Maybe Rick has Frozen Brain Syndrome too :)
 
bladsmth said:
Japanese style knives take this even farther, as they have very thin edge geometry. This is the realm of the high wear and high hardness stainless steels, and the higher carbon steels. 1095, 52100, W2, are all a better choice than 1084.
For the ultimate steel choice in making Japanese kitchen knives, Hitachi blue or white steel is the steel of choice.
Click to expand...
Where would O-1 fit in this puzzle? I have found a source of O-1 that is very close in price to 1095 and 52100 and seems to be a little easier to heat treat. Do you know of a US source for the blue or white steel for low volume buyers? I found a source but they sold tons, not pounds.
scott
 
bladsmth said:
The carbides in 1095/W2 are not the same as the big alloy carbides in stainless steel. We are talking about simple iron carbide here. If the steel is normalized starting at a high enough temp, and held long enough for the carbides to go fully into solution, then the grain is reduced with subsequent quenches from lower temps, the harder edge of the higher carbon steel will be a better cutter because it will last longer. The 1084 edge will be about the same fineness of grain, maybe a tad finer, but that will not make any difference in cutting ability. A very thin edge on the 1084 will be gone after only a few cuts. The higher carbon blade will have a harder and tougher edge and thus cut better and longer.
Click to expand...

Time to go ahead and pony up for some steel I'll have to send off for heat treat I guess.
 
Rick Marchand said:
When matching steel with intended usage, I tend to separate it by the three steel types. Not always... but it is a decent starting point.

Slicers that require high hardness - Hypereutectoid
General cutters and utility knives - Eutectoid
Choppers and blades that would see impact - Hypoeutectoid
Click to expand...

I have some 3/16" thick 1084 I intend to use for a couple of outdoor choppers with overall lengths of 20".

What are the drawbacks, if any, to using 1084 (which I undertsand is eutectoid) for choppers, and what can you recommend to mitigate these (suggestions to design, geometry, etc.)? I was simply thinking to have Rob heat treat them to about 59 or so. Thanks!
 
This is a six year old thread.

Not sure what Storm W's answer was about, but to answer your question about 1084 -

1084 is a perfectly good steel for choppers and other camp knives. Its biggest advantage for new makers is the ease of HT. 1095, 52100,stainless steels, etc. are more complex to do HT on.

I would have your HT guy do the 1084 at Rc 60 for your camp knife.
 
Stacy E. Apelt - Bladesmith said:
This is a six year old thread.

Not sure what Storm W's answer was about, but to answer your question about 1084 -

1084 is a perfectly good steel for choppers and other camp knives. Its biggest advantage for new makers is the ease of HT. 1095, 52100,stainless steels, etc. are more complex to do HT on.

I would have your HT guy do the 1084 at Rc 60 for your camp knife.
Click to expand...
Sorry Stacy I didn't notice the old thread. I was replying to someone long gone. Seamed like the guy was having a hard time picking steel by both price and edge retention without sounding like he was wanting a traditional steel. 1084 is great but if I was sending it out I would sure want something a lot more wear resistant and hopefully stainless. Oppps:rolleyes:
 
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